|Publication number||US7466849 B2|
|Application number||US 11/473,771|
|Publication date||Dec 16, 2008|
|Filing date||Jun 23, 2006|
|Priority date||Jun 23, 2005|
|Also published as||DE102005029242A1, DE102005029242B4, US20070012880|
|Publication number||11473771, 473771, US 7466849 B2, US 7466849B2, US-B2-7466849, US7466849 B2, US7466849B2|
|Inventors||Sultan Haider, Peter Kreisler|
|Original Assignee||Siemens Aktiengesellschaft|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (16), Referenced by (4), Classifications (13), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention concerns a method for acquisition and evaluation of image data of an examination subject that are generated with at least one medical imaging apparatus as well as an associated apparatus.
2. Description of the Prior Art
In the framework of the examination of a patient, exposures are often produced with medical imaging apparatuses in order, for example, to generate a diagnosis or a finding or to be able to plan a therapy. It is thereby frequently not sufficient to produce an exposure or an exposure series once with an examination apparatus. Rather, exposures are often acquired at specific time intervals, for example to monitor a recovery or an etiopathology (course of a disease), possibly also exposures of other body regions insofar as new diseases could occur or interactions are to be monitored.
An examination with different examination apparatuses (for example with a computed tomography apparatus, a magnetic resonance system or a ultrasound apparatus) is additionally frequently necessary for a concluding examination that enables a qualified diagnosis and treatment. The produced image exposures are normally spatially associated with each other using a coordinate system that is predetermined by the examination apparatus. Alternatively, patient-specific coordinate systems that are specific to the respective examination and the directly-observed examination region can be used.
In the use of apparatus-specific coordinate systems, there is the problem of the comparability of exposures that have been produced with different apparatuses. With region-related patient coordinate systems, there is the problem that exposures of other body regions or exposures with different orientations cannot be arranged or compared, or can only be arranged or compared with difficulty. It is extraordinarily difficult to interpret exposures that were produced with different apparatuses or at different times, or of different examination regions, in the evaluation and the subsequent finding.
An object of the present invention is to provide a method for acquisition and evaluation of image data of an examination subject that are obtained with at least one medical imaging apparatus, which allows a faster and qualitatively better evaluation compared to conventional methods.
This object is achieved in accordance with the invention by a method that includes the steps of:
Generating a whole-body overview image of the examination subject and selection of an anatomical region in the whole-body overview image.
Establishing a point in the selected anatomical region, this point forming the origin of a whole-body coordinate system relating to the examination subject, and establishing an associated, subject-related coordinate system.
In a later examination with a medical examination apparatus, re-creating a whole-body overview image and/or a partial image including the origin and/or another marker point, and generating examination images of the examination subject.
With the aid of the new whole-body overview image and/or the partial image, spatially arranging the examination (diagnostic) images in the original whole-body coordinate system dependent on a comparison of at least one item of image information of the examination image with at least one item of image information of the whole-body overview image and/or at least one item of information of the partial image that is related to the whole-body coordinate system.
According to the invention, a whole-body overview image of an examination subject (for example a person or an animal) is thus produced before the generation of one or more actual diagnostic images. This whole-body overview image is used as an examination guide, and is shown on a display or monitor. This overview image completely reproduces the body of the examination subject, allowing specific anatomical regions (such as the head, the chest, the abdomen or also the arms and legs) to be differentiated.
Such an anatomical region is selected in the whole-body overview image by electronic interaction with the overview image, and a point that represents the origin of a coordinate system regarding the entire body of the examination subject is established within this selected anatomical region. This point forming the origin can be a specific point in the body of the examination subject that is used in examinations such as what is known as an anatomical marker, for example the clavicle protuberance or a specific vertebra or a back prominence and the like. A coordinate system that represents a whole-body coordinate system for the respective examination subject is established with regard to this origin point. An orthogonal trihedron with axial directions is appropriately selected for this coordinate system, the axial directions thereof corresponding to the body-relative axes normally used in anatomy.
Finally, examination images of the examination subject can be created with a medical imaging apparatus, and these examination images can be spatially associated with the whole-body coordinate system using the whole-body overview image, with the position of the anatomical information represented as image information in the examination images being established clearly (namely with regard to the coordinate system defined above). It is likewise possible to implement an examination only later or to implement one or more follow-up examinations in the event that examination images have already been acquired and arranged in the coordinate system as described in the preceding. Such follow-up examinations, if applicable, can be implemented with other medical examination apparatuses. It is thus possible for an x-ray exposure to be made initially with ultrasound exposures being produced in the framework of a subsequent examination.
If a later examination (that can be a follow-up examination) is undertaken, a whole-body overview image and/or a partial image are thus re-created, the partial image showing not the entire body but rather a section thereof that contains the origin point and/or another marker point. Like the first overview image, this overview image or, respectively, partial image serves as a reference image and is accordingly stored. The new whole-body overview image or partial image serves for the determination of the coordinates for the examination images to be acquired now in order to be able to arrange these spatially in the original whole-body coordinate system. For this purpose, a comparison of at least one item of image information of the examination (diagnostic) image with at least one item of image information of the whole-body overview image and and/or at least one item of information of the partial image that relates to the whole-body coordinate system is implemented. An image processor can be used that compares the image data of the different images and detects commonalities, for example also with the aid of defined anatomical regions or markers. The result of the spatial arrangement can ultimately be displayed on an image output unit as a whole-body image and/or partial image with which examination images (which are possibly shown with lower resolution or merely as outlines) placed within this overview image are shown.
The inventive method thus offers the possibility to quickly compare examination images of examinations that have occurred at different points in time or were implemented with different apparatuses using the spatial arrangement in the whole-body coordinate system. Through the knowledge of the associated coordinates of the whole-body coordinate system, it is immediately clear where the respective image is to be arranged in the patient body and how it compares with earlier exposures for evaluation. If a doctor or technician who is occupied with the evaluation of the image data searches for exposures of specific regions, he or she can simply search through a data processing device by specification of the coordinates of the whole-body coordinate system. Like the examination planning, the navigation through the (often large) quantity of image data is significantly simplified; reference to a single coordinate system that can be maintained unchanged for all examinations of the respective patient now suffices. The quality of the coverage thus can be distinctly improved while at the same time the examination planning (for example given the production of real-time exposures) is simplified.
According to the invention, the electronic interaction with the overview image (or the data representing the overview image) for selecting the anatomical region can be selected automatically and/or on the part of the user. An automatic selection can ensue, for example, such that a marked ariatomical region is defined dependent on the apparatus that is used for generation of the whole-body overview image in the context of its predominant usage. This automatic selection, for example, can be predetermined by an operator of an examination apparatus or can be pre-selected by a program. It is likewise possible for the anatomical region to be selected by the user, such as by a region that is pre-selected at a default selection being replaced by another.
Furthermore, in accordance with the invention the user can select the anatomical region freely or from a number of predetermined regions. It is possible for various separated regions (for example separated or boxed off from one another by lines) to be shown to the user in the whole-body overview image, with additional text information (such as, for example, “head” or “thorax”) also being possibly presented. Such predetermined regions can also be indicated with different colors. A free selection is alternatively possible, for example such that the user enters selection boxes or intersecting lines via an input device with an associated image processing functionality of a program in order to specify the boundary of the desired region.
Predetermined anatomical regions can be determined in accordance with the invention using geometric data and/or fitting algorithms and/or decision rules. Functionalities hereby also can be determined that are already implemented anyway for the required image evaluation in medical imaging apparatuses. To determine the anatomical regions using geometric data, for example, data are used that determine proportions in the human body or that show and compare typical specifications for intervals between marked anatomical points. Fitting algorithms detect specific curve contours, so that a reference to an anatomical region can be produced based thereon. To establish boundaries, decision rules (such as, for example, practical knowledge (know-how as well) can be employed by a computer using connections that occur frequently or always in the transition from different anatomical regions into one another, for example from the spinal column into the head region.
The point in the selected anatomical region that forms the origin of the whole-body coordinate system can be established automatically, in particular as a center and/or internal point of the region. Particularly within a large anatomical region, a less mobile structure (for example in the center) can be selected, for example with a relation to the shown bone structures or organs. It can also be appropriate to establish a point as the origin is different from the center, such as an inner point of the region that is again less mobile. Pathological findings (for example in the center of an anatomical region fittingly selected for monitoring) can be made that form the basis for subsequent examination images to be produced, in which case the image center naturally can be different from the center of an organ or a structure. In particular for small anatomical regions, it can be meaningful to select an eccentric origin point, for example in order to avoid the origin of the whole-body coordinate system (disadvantageous for representation purposes) from falling into the region of a possible pathological finding, whereby the risk additionally exists that anatomical variations may arise within this pathological region due to effected operations or the like. The internal point of the region in the sense of the invention can also be a known anatomical marker; such a one can thus be specified in the selected anatomical region.
The whole-body overview image and/or partial images (that, for example, were created in the framework of different examinations) can be mapped to one another, particularly by means of an iterative error correction method. Initially only rough correlations and deviations are determined, for example in order to implement a size adaptation, whereupon corrections can then be implemented step-by-step using specific image information. Such a superimposition of the whole-body overview images or partial images that were produced at various points in time enables errors to be avoided in the arrangement of the examination images in the original whole-body coordinate system, since inconsistencies as well as fundamental differences (for example with regard to the orientation) can be detected and accounted for with the mapping of the overview images or partial images to one another.
The (at least one) whole-body image and/or partial image preferably is (are) created with a medical imaging apparatus, in particular with the same examination apparatus as the examination (diagnostic) images. For example, what is known as a pre-scan can be produced for this purpose in which a complete localization of the body is created by moving a patient table on which the patient is located is moved. The overview image or partial image in this manner created not only enables a sufficiently-detailed anatomical orientation in order to establish an anatomical region, but also can be used in order to obtain fundamental examination results that are relevant for the planning of the further examination, such as, for example, the presence of distinct anatomical anomalies.
Furthermore, at least one overview image and/or partial image can be created using at least one image acquisition modality, in particular a camera and/or a laser system, and/or with the aid of a program. Such a procedure is particularly suited when an examination with diagnostic image acquisitions should not follow immediately or an examination apparatus is used with which whole-body exposures are not possible, or which would entail an unnecessarily high exposure of the patient (for example by radiation). In such a case, additional image acquisition modalities can be connected via corresponding input and output connections, in particular to the control device of a medical examination apparatus. Depending on the desired precision or detail resolution or preferred type of later representation, cameras in the optical or in the infrared range can be used as well as laser systems that scan the body. Alternatively, an overview image or partial image of a computer program can be used, for example a simple pictogram of the human body that, if applicable, is made more precise by individual specifications regarding the examination subject (such as size or weight). An overview image creation or partial image creation by means of a combination of various techniques is possible, for example an image acquisition with a camera or the like and a subsequent image processing with the aid of a program.
An image with lower resolution can be created as the overview image and/or partial image. The resolution must merely be sufficient to allow determination of an anatomical region. The generation of an overview image or partial image with resolution sufficient in this regard offers the advantage that this can be acquired more quickly than a high resolution image, while at the same time the image data quantity is limited.
In addition to the origin, at least one further point preferably is established as a marker in the whole-body overview image. Such further point serves as a marker in addition to the origin and can be automatically determined, for example using a geometric sectioning of the overview image or as an anatomically distinguished point. It is likewise possible for the doctor or technical assistant implementing the examination to determine one or more further points as markers, if applicable as a result of a prior selection of further anatomical regions. This can ensue, for example, with regard to the underlying pathological condition that is present in the respective patient.
For example, additional markers enable the use of the established whole-body coordinate system even when anatomical alterations occur in the patient that lead to the situation that an original marker or origin point can no longer be used. This can be the case, for example, when a tumor forms or when operative procedures ensue that entail anatomical changes. It is likewise possible that a patient has an accident that causes irreparable injuries, such that the origin point can no longer be determined. Given determination of additional markers, the whole-body coordinate system nevertheless still can be used as a coordinate system forming the basis of all examinations with imaging apparatuses, available for the lifespan of the patient. With increasing age, however, a matching or an adaptation is desirable.
The examination images additionally can be arranged in an examination-based coordinate system. For example, in the case of a magnetic resonance examination such an examination-based coordinate system is based on the position of the magnet and is advantageous for monitoring the positioning of the produced images with regard to this specific examination apparatus. An additional spatial reference possibility results by the use of such an examination-based coordinate system, whereby the possibilities for examination evaluation are further improved.
Magnetic resonance apparatuses and/or computed tomography apparatuses and/or x-ray apparatuses and/or positron emission apparatuses and/or ultrasound systems can be used as imaging medical examination apparatuses. The use of all imaging methods in medicine is generally conceivable, for example all corresponding nuclear medicine methods. Should the overview images also be created with the imaging medical examination apparatus, an examination apparatus is thus to be used that enables whole-body examinations. With the whole-body coordinate system according to the invention it is then possible to spatially arrange all medical image exposures in the uniform whole-body coordinate system that is defined once.
It is furthermore advantageous for information about the whole-body coordinate system is integrated into standardized image information. Such standardized image information is normally created as a “header” with regard to all image exposures and is later transferred with these exposures (i.e., the image data thereof possibly for forwarding the exposures. Here, for example, the position of the patient or the orientation during the acquisition, the acquisition time as well as duration is stored. An already-present information system can thus be used in order to store additional information with regard to the whole-body coordinate system.
Based on the whole-body overview image, possible movement of the examination subject given the generation of the examination images can be detected and/or calculations can be corrected. For this purpose, a comparison of the examination images with the overview image is implemented, and this can be implemented with less time with the aid of fit algorithms, for example an approach that is based on the nearest approximation.
Moreover, the above object is achieved in accordance with the present invention by an apparatus for acquisition and evaluation of image data of an examination subject that are generated with at least one imaging medical examination apparatus, the apparatus being designed for implementation of the method as described.
Such an apparatus normally includes a server at which the incoming image data are stored centrally. In addition, generally more than one examination apparatus will be present, for example a magnetic resonance tomography apparatus, a computed tomography apparatus and an x-ray apparatus and ultrasound apparatus. The examination apparatuses respectively possess some control devices that in turn include a computer and an image output unit that is operated by a doctor or medical assistant via a corresponding input device. The apparatuses as well as the central server are connected with one another via a network, such that with an appropriate authorization, access is possible to image data that were acquired earlier in the framework of a first examination with the same or a different examination apparatus. Should a follow-up examination now be implemented, for example with a magnetic resonance tomography apparatus, an overview image is in turn created as a pre-scan. The actual examination images are subsequently acquired. The new examination images can be arranged in multi-dimensional coordinate space with the whole-body coordinate system already determined in a preceding examination, whereupon a comparison of image information of the examination images with the new whole-body overview image is implemented.
In the whole-body overview image 1, the doctor or medical assistant who operates the examination apparatus selects an anatomical region with the mouse point Z, by drawing a selection box 3 with the mouse pointer Z by means of an image processing program. In step S2, the selected anatomical region 2 (which here corresponds to a segment of the spinal column) is shown enlarged. A point forming the origin of a whole-body coordinate system with regard to the examination subject is established by drawing a further selection box 4, again by means of the mouse pointer 4. This occurs via a program that selects an anatomically-appropriate point within the selection box 4 (that here was extended over a specific vertebra). This origin point is designated with P. Starting from the origin point P, a whole-body coordinate system is determined with orthogonal axes that correspond to the typical axial directions in the anatomy relative to the body.
In step S3, a follow-up examination with a different examination apparatus is finally implemented. A whole-body overview image 5 is acquired again, which here is an overview image that was created with a camera, thus not the actual medical imaging apparatus. The camera image shows the patient again in a lateral view. The camera image is used in this case in order to keep the radiation exposure due to the medical imaging apparatus as low as possible. After the creation of the whole-body overview image 5, subsequent examination images 6 a through 6 c are acquired that show the head, neck and shoulder regions of the patient.
For step S4, the whole-body overview image 5 is shown again, but this time with the whole-body coordinate system with the origin point P as well as the axes A as it was established in step S2. Furthermore, the examination images 6 a through 6 c are shown in their spatial arrangement in the whole-body coordinate system with the origin point P. This arrangement occurred based on a comparison of at least one item of image information of the respective examination images 6 a through 6 c with at least one item of image information (relative to the origin point P) of the newly-created whole-body overview image 5. One or more selected points of the examination images 6 a and 6 c that can be inserted into the coordinate system using the position of the corresponding points in the whole-body overview image 5 (which can be associated with the whole-body coordinate system) serve as such image information. In addition to this, curve contours of anatomical structures can be taken into account. The arrangement, if applicable, can be augmented by a superimposition of both overview images, which is not shown here.
Within the overview image, the operator of the control device 12 now selects an anatomical region of interest, appropriately the region at which an examination should be implemented. The selection of this anatomical region ensues from a series of predetermined regions. After the selection of the anatomical region by the operator of the control device 12, an origin point for a whole-body coordinate system to be determined is automatically established using a program stored in the computer 12 a. The coordinate system is ultimately established dependent on axes that are predetermined or can be selected as needed. The actual examination exposures are subsequently finished and arranged in the whole-body coordinate system as well as in a coordinate system specific for the measurement apparatus.
The control device 12 of the magnetic resonance apparatus 8 is connected via a network N with other control devices (such as the control device 13, having a computer 13 a with an image output unit 13 b and a input device 13 c, which belongs to an x-ray apparatus 14). The connection of the network N to further control devices is indicated by the arrow P′. A connection additionally exists to a server system 15 that is equipped (via a computer 15 a with an image output unit 5 b and an input device 15 c) for operation by an administrator. The image exposure data as well as the overview images that serve as a reference are centrally stored in the computer 15 a. Should these be viewed at a control device 12 or 13, an access to the server 15 ensues.
If the patient is now re-admitted to the hospital for a follow-up examination with the x-ray apparatus 14, a whole-body overview image of the patient (located on the patient bed 17 for this) is now acquired in turn by means of a camera 16. This overview image is initially stored in the computer 13 a of the control device 13 and displayed on the image output unit 13 b. The actual examination images of the examination subject are subsequently finished with the x-ray acquisition unit 18. These are subsequently arranged in the original whole-body coordinate system by a comparison with the information of the new whole-body overview image, in that characteristic values (the position of anatomical points and the like) are compared. After a post-processing (ensuing, if applicable, on the control device 13), the new whole-body overview image as well as the examination images suitable for further usage are transmitted to a computer 15 a of the server system 15. A fast discovery of images without problems is inventively possible for a specific region unambiguous established by the whole-body coordinate system; only the corresponding coordinates must be specified. The quality of the examination reports is clearly improved while at the same time a simple navigation is possible in the examination planning or also in the subsequent evaluation.
In addition, further marker points M in the coordinate system established via the origin point with corresponding associated axes are specified that correspond to points in the body of the patient that can be determined well in image examinations. These additional marker points M allows the coordinate system that is established via the origin point to also be used when the original marker point U can no longer be used due to anatomical changes, for example due to an accident or an operation. After the establishment of the whole-body coordinate system as well as of the further marker points M, the actual examination exposures for the anatomical region of the right leg can be produced, whereby the whole-body coordinate system is available at any time in further examinations for unambiguous association of the examination images then produced, independent of the apparatus-specific coordinate systems as well as patient-related coordinate systems limited to a specific acquisition region.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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|U.S. Classification||382/128, 600/407|
|Cooperative Classification||A61B6/00, A61B6/463, A61B6/5229, A61B6/469, A61B6/5241|
|European Classification||A61B6/46B4, A61B6/52D6, A61B6/46D4, A61B6/52D6B2, A61B6/00|
|Sep 8, 2006||AS||Assignment|
Owner name: SIEMENS AKTIENGESELLSCHAFT, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HAIDER, SULTAN;KREISLER, PETER;REEL/FRAME:018347/0750;SIGNING DATES FROM 20060705 TO 20060707
|May 11, 2012||FPAY||Fee payment|
Year of fee payment: 4